The removal of aniline as a carcinogen from aqueous environments is highly significant. In the present study, the feasibility of photocatalytic degradation of aniline by CuO nanoparticles was evaluated. A batch reactor with an internal UV lamp was used and the effects of the parameters of pH (3–11), dosage of catalyst (0.01–0.1 g/L), initial concentration of aniline (50–250 mg/L), and duration of reaction (15–90 min) were investigated. The remaining concentration of aniline was determined by spectrophotometer at the wavelength of 198 nm. The Langmuir–Hinshelwood model was used for examining the kinetics of the reaction. The results showed that the degradation of aniline is maximum at pH 7. Also, the removal efficiency of 90.16% after 90 minutes of reaction in the case of initial concentration of 50 mg/L was obtained. The aniline degradation was elevated from 40 to 82% by increasing CuO nanoparticles’ dosage from 0.01 to 0.1 g/L. In addition, the obtained data properly fit with the Langmuir–Hinshelwood kinetic model and showed that the Kapp decreased from 0.029 to 0.016 min−1 by increasing of the initial concentration of aniline. Considering the obtained results, the UV/CuO process can be an effective method for removing aniline from aqueous solution.